[libc++] Fix debug_less test in C++03
[libc++] Fix debug_less test in C++03

We were using C++11 features but the test needs to work in C++03 too.

git-svn-id: 756ef344af921d95d562d9e9f9389127a89a6314@358433 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx